CVE catalog
CVE-2021-43523
uclibc: CVE-2021-43523
- Severity
- Critical · CVSS 9.6
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 3.07% · Oct 25, 2026
In uClibc and uClibc-ng before 1.0.39, incorrect handling of special characters in domain names returned by DNS servers via gethostbyname, getaddrinfo, gethostbyaddr, and getnameinfo can lead to output of wrong hostnames (leading to domain hijacking) or injection into applications (leading to remote code execution, XSS, applications crashes, etc.). In other words, a validation step, which is expected in any stub resolver, does not occur.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | uclibc | sid | 1.0.54-1 | vulnerable |
| Debian | uclibc | forky | 1.0.54-1 | vulnerable |
| Debian | uclibc | trixie | 1.0.35-1 | vulnerable |
| Debian | uclibc | bookworm | 1.0.35-1 | vulnerable |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | uclibc | source | sid | (unfixed) | unimportant | Not reported | Not reported |
| Debian | uclibc | source | forky | (unfixed) | unimportant | Not reported | Not reported |
| Debian | uclibc | source | trixie | (unfixed) | unimportant | Not reported | Not reported |
| Debian | uclibc | source | bookworm | (unfixed) | unimportant | Not reported | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [uclibc-source]Affected
Source package: [uclibc]
Details (2)
1.0.35-1· all · bookwormAffected
dsa · uclibc · debian · bookworm; dsa · uclibc · debian · 12
1.0.35-1· all · bookwormAffected
dsa · uclibc · debian · bookworm; dsa · uclibc · debian · 12
[Debian 13 (Trixie)]
- [uclibc-source]Affected
Source package: [uclibc]
Details (2)
1.0.35-1· all · trixieAffected
dsa · uclibc · debian · 13
1.0.35-1· all · trixieAffected
dsa · uclibc · debian · 13
Observed:
References
- [https://osv.dev/vulnerability/DEBIAN-CVE-2021-43523]
- [https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2023/icsa-23-234-01.json]
- [https://security-tracker.debian.org/tracker/CVE-2021-43523]
[CISA cybersecurity advisories] · [Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database]